The previous hack wasn't thread-safe: read-only access would
access the reference counter multiple times at the same time,
which therefore would have to be thread-local to ever work.
The current solution just disables the calls to lock/unlock
for copyconstructed objects, which works if the copyconstructed
object isn't used anymore after the original is destructed.
This is the case then the copy construction only happens
upon passing a temporary to a function, which is the case.
g++ 4.2 (and possibly earlier) apparently call a copy
constructor when passing a temporary to a function
that takes a const reference. Added code to allow
copy-constructing the AI*Access classes for this
compiler.
g++-4.2.x also bails out when it encounters files that
do not end on a newline. So, also added those where
they were missing.
